Precompensation (e.g., Prechirping, Predistortion Patents (Class 398/193)
  • Patent number: 10097280
    Abstract: A signal pre-compensation system analyzes one or more properties of a communication medium and, taking advantage of the locality of propagation, generates using sparse fast Fourier transform (sFFT) a sparse kernel based on the medium properties. The system models propagation of data signals through the medium as a fixed-point iteration based on the sparse kernel, and determines initial amplitudes for the data symbol(s) to be transmitted using different communication medium modes. Fixed-point iterations are performed using the sparse kernel to iteratively update the initial amplitudes. If the iterations converge, a subset of the finally updated amplitudes is used as launch amplitudes for the data symbol(s). The data symbol(s) can be modulated using these launch amplitudes such that upon propagation of the pre-compensated data symbol(s) through the communication medium, they would resemble the original data symbols at a receiver, despite any distortion and/or cross-mode interference in the communication medium.
    Type: Grant
    Filed: October 3, 2016
    Date of Patent: October 9, 2018
    Assignee: Significs & Elements, LLC
    Inventor: Pierre-David Letourneau
  • Patent number: 10050739
    Abstract: An Internet Protocol/Wave Division Multiplex (IP/WDM) machine implements Hardware Root of Trust (HRoT). In the IP/WDM machine, an IP router exchanges IP packets between IP ports and WDM interfaces based on IP control data. A WDM switch exchanges the IP packets between the WDM interfaces and WDM ports based on WDM control data. The WDM ports exchange the IP packets using different optical wavelengths. Data processing circuitry transfers HRoT data indicating the optical wavelengths used to exchange the IP packets and indicating an encoded hardware key that is physically-embedded in the IP/WDM machine.
    Type: Grant
    Filed: February 9, 2017
    Date of Patent: August 14, 2018
    Assignee: Sprint Communications Company L.P.
    Inventors: Ronald R. Marquardt, Lyle Walter Paczkowski, Arun Rajagopal
  • Patent number: 9859976
    Abstract: A method and an apparatus are provided, for monitoring OSNR system margin in optical networks, by relying on relationships that exists between the Optical Signal to Noise Ratio (OSNR) value and the Electrical Signal to Noise Ratio (ESNR) value.
    Type: Grant
    Filed: February 18, 2015
    Date of Patent: January 2, 2018
    Assignee: ECI Telecom Ltd.
    Inventors: David Jimmy Dahan, David Jacobian
  • Patent number: 9407375
    Abstract: An optical system may have an optical transmitter including a digital signal processor to receive a signal channel, determine a digital signal associated with the signal channel based on information in a look-up table and based on a test tone, and output the digital signal. The optical system may further have a digital-to-analog converter to convert the digital signal to an analog signal, a laser to provide an optical signal, and a modulator to receive the optical signal and the analog signal, and modulate the optical signal based on the analog signal to form a modulated optical signal. The optical system may also have a photodiode to convert the modulated optical signal to a digital signal, a tone detector to detect the test tone based on the digital signal, and a controller to modify the information in the look-up table based on the test tone.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: August 2, 2016
    Assignee: Infinera Corporation
    Inventor: Jeffrey T. Rahn
  • Patent number: 9300407
    Abstract: An apparatus comprising an optical receiver configured to receive a plurality of orthogonal frequency-division-multiplexed (OFDM) symbols comprising a first OFDM symbol and a second OFDM symbol, and a processor coupled to the optical receiver and configured to generate a first decoded signal based on the first OFDM symbol, estimate a plurality of channel parameters adaptively based on the first decoded signal, generate a second decoded signal based on the second OFDM symbol, wherein the second decoded signal is generated using the plurality of channel parameters, and wherein phase recovery is performed on the first OFDM symbol using a number of pilot subcarriers prior to generating the first decoded signal.
    Type: Grant
    Filed: August 28, 2013
    Date of Patent: March 29, 2016
    Assignee: Futurewei Technologies, Inc.
    Inventors: Mahdi Zamani, Zhuhong Zhang, Chuandong Li
  • Patent number: 9264144
    Abstract: A dual-polarization, 4-subcarriers orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 4-subcarriers OFDM signal as a 25-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method.
    Type: Grant
    Filed: October 22, 2014
    Date of Patent: February 16, 2016
    Assignee: ZTE Corporation
    Inventors: Jianjun Yu, Fan Li
  • Patent number: 9191111
    Abstract: A modulated optical system with cross-modulation compensation reduces or corrects cross-modulation that might occur in a multichannel RF signal modulating a laser. The system detects the cross-modulation, for example, by detecting an envelope of the RF signal or by detecting RF power fluctuations, generates a cross-modulation detection signal, and imparts a compensating cross-modulation by adjusting a bias current of the laser in response to the cross-modulation detection signal.
    Type: Grant
    Filed: October 3, 2008
    Date of Patent: November 17, 2015
    Assignee: Applied Optoelectronics, Inc.
    Inventors: Jun Zheng, Brian Ishaug
  • Patent number: 9166704
    Abstract: In an example, the present invention includes an integrated system on chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. The device also has an interface configured to communicate between the silicon photonics device and the control block.
    Type: Grant
    Filed: July 3, 2014
    Date of Patent: October 20, 2015
    Assignee: Inphi Corporation
    Inventor: Radhakrishnan Nagarajan
  • Patent number: 9048954
    Abstract: In one embodiment, the invention provides an optical interconnect comprising a transmitter for generating and transmitting an optical signal, a receiver for receiving the optical signal from the transmitter and for converting the received optical signal to an electrical signal, and a pre-transmitter distort circuit for applying a pre-transmitter distort signal to the transmitter to adjust the shape of the optical signal generated by the transmitter. Distortions are introduced into the optical signal when the optical signal is generated, transmitted to the receiver, and converted to the electrical signal. As a result of the signal applied to the transmitter by the pre-transmitter distort circuit, the optical signal generated by the transmitter has distortions to compensate for the distortions introduced into the optical signal, wherein the electrical signal, into which the optical signal is converted, has a desired shape.
    Type: Grant
    Filed: March 2, 2011
    Date of Patent: June 2, 2015
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Alexander V. Rylyakov, Clint L. Schow
  • Patent number: 9037002
    Abstract: A pre-emphasis control method includes calculating an average value of transmission characteristics based on transmission characteristics of a plurality of light beams received by a receiver, and determining that, among signals of the plurality of light beams, a wavelength with a deviation from the average value is a wavelength at which control is to be performed, determining that the wavelength at which control is to be performed and a wavelength adjacent thereto are a group of wavelengths at which control is to be performed, obtaining an average of transmission characteristics of the group of wavelengths at which control is to be performed, and based on a difference between averaged transmission characteristics and respective transmission characteristics of the group of wavelengths at which control is to be performed, changing a light intensity output from each transmitter that transmits a group of wavelengths at which control is to be performed.
    Type: Grant
    Filed: November 10, 2011
    Date of Patent: May 19, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Jyunji Tanaka, Shinichi Kaneko, Takeo Osaka
  • Patent number: 9036736
    Abstract: A method and apparatus for controlling update of digital pre-distortion (DPD) coefficient is provided. The apparatus is applicable to a digital power control system, wherein the apparatus comprises: an update controlling unit configured to determine a group of fully-trained DPD coefficients among a plurality of DPD coefficients; and a DPD coefficient generating unit configured to update adaptively the group of fully-trained DPD coefficients according to the result of judgment of the update controlling unit. The DPD coefficients are allowed to be updated after being judged as being able to be fully trained according to power distribution information of DPD input signals, or according to address distribution information of an LUT, or according to average power of output of an HPA; otherwise, they may not be updated, thereby efficiently preventing DPD abnormality resulted from unfull training of coefficients in being updated.
    Type: Grant
    Filed: August 20, 2013
    Date of Patent: May 19, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Pei Chen, Jianmin Zhou, Takanori Iwamatsu
  • Patent number: 9031178
    Abstract: Systems that allow for DFE functionality to be eliminated from the receiver side of a communication system and for a DFE-like functionality to be implemented instead at the transmitter side of the communication system are provided. By removing the DFE functionality from the receiver side, error propagation can be eliminated at the receiver and receiver complexity can be reduced drastically. At the transmitter side, the DFE-like functionality provides the same DFE benefits, and with the transmitter environment being noise-free, no errors can occur due noise boosting, for example. The DFE-like functionality at the transmitter side can be implemented using non-linear (recursive or feed-forward) pre-coders or a combination of non-linear pre-coders and linear filters, which can be configured to invert a net communication channel between the transmitter and the receiver. Embodiments particularly suitable for fiber optic channels and server backplane channels are also provided.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: May 12, 2015
    Assignee: Broadcom
    Inventors: William Bliss, Vasudevan Parthasarathy
  • Patent number: 9031415
    Abstract: An Ethernet adapter system may include a transmitter to insert a payload type identifier sequence in a generic frame procedure header to indicate that a network is a converged enhanced Ethernet network. The transmitter may insert idle sequences in a stream of data frames transmitted along a link. The system may include a receiver to recognize a condition and to force a loss of synchronization condition on the link that will be converted by the receiver into a loss of light condition. The receiver may scan the transmitted stream of data frames for invalid data frames and introduce a code into the stream of data frames whenever an invalid data frame is detected.
    Type: Grant
    Filed: December 8, 2012
    Date of Patent: May 12, 2015
    Assignee: International Business Machines Corporation
    Inventors: Casimer M. DeCusatis, Thomas A. Gregg, Rajaram B. Krishnamurthy
  • Patent number: 9020067
    Abstract: Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion.
    Type: Grant
    Filed: April 1, 2013
    Date of Patent: April 28, 2015
    Assignee: Broadcom Corporation
    Inventors: Thomas J. Kolze, Bruce J. Currivan, Ramon A. Gomez
  • Patent number: 9020362
    Abstract: A transceiver architecture for wireless base stations wherein a broadband radio frequency signal is carried between at least one tower-mounted unit and a ground-based unit via optical fibers, or other non-distortive media, in either digital or analog format. Each tower-mounted unit (for both reception and transmission) has an antenna, analog amplifier and an electro-optical converter. The ground unit has ultrafast data converters and digital frequency translators, as well as signal linearizers, to compensate for nonlinear distortion in the amplifiers and optical links in both directions. In one embodiment of the invention, at least one of the digital data converters, frequency translators, and linearizers includes superconducting elements mounted on a cryocooler.
    Type: Grant
    Filed: September 4, 2012
    Date of Patent: April 28, 2015
    Assignee: Hypres, Inc.
    Inventors: Deepnarayan Gupta, Oleg Mukhanov
  • Patent number: 9020021
    Abstract: An apparatus for encoding data signals includes a transmitter configured to encode and transmit a data signal over a communication channel, the transmitter including a precoder; a signal shaper configured to adjust the data signal by applying an equalization setting to the data signal, the equalization setting including an amplitude and offset and transmit the adjusted data signal to the precoder; and a processing unit. The processing unit is configured to perform: receiving channel coefficients associated with the communication channel; for each of a plurality of amplitude settings and a plurality of offset settings, calculating whether a modulo amplitude level would occur at a receiver using a modulo operation; selecting the equalization setting from the plurality of amplitude settings and the plurality of offset settings based on the calculation; and transmitting a control signal specifying the equalization setting to the signal shaper.
    Type: Grant
    Filed: July 29, 2013
    Date of Patent: April 28, 2015
    Assignee: International Business Machines Corporation
    Inventors: Marcel A. Kossel, Daihyun Lim, Pradeep Thiagarajan
  • Patent number: 9014571
    Abstract: A pluggable small form factor optical transmitter is described. The optical transmitter can be plugged into an optical transmission unit which may hold many optical transmitters. The optical transmitter includes an analog laser for QAM transmissions, a TEC driver, pre-distortion circuitry, a microprocessor, and an automatic power control circuit and dither tone level control capability. The optical transmitter may have receptacle optical ports such as LC or SC type, also it may include a pin connector for mating with the optical transmission unit and a latch mechanism to secure the optical transmitter in the optical transmission unit.
    Type: Grant
    Filed: November 1, 2006
    Date of Patent: April 21, 2015
    Assignee: ARRIS Technology, Inc.
    Inventors: Ihab E. Khalouf, Philip Miguelez, Alfred J. Slowik
  • Patent number: 9014568
    Abstract: An optical access network with centralized digital optical line termination OLT including an optical line termination unit having a digital transmitter and a coherent receiver for downstream signal transmitting and upstream signal receiving, and at least one optical network unit ONU with transceiver functions for communicating with the OLT over an optical path, the ONU including intensity modulation and single photodiode detection, wherein the digital transmitter includes digital signal processing DSP, digital-to-analog conversion DAC and analog-to-digital conversion ADC functions that can be shared by all multiple ones of the ONU in the network, the DSP reducing or removing dispersion and non-linearity effects in the network and the coherent receiver enabling performance of the downstream stream signal transmitting to match that of the upstream signal receiving in the OLT.
    Type: Grant
    Filed: February 15, 2013
    Date of Patent: April 21, 2015
    Assignee: NEC Laboratories America, Inc.
    Inventors: Dayou Qian, Ting Wang
  • Publication number: 20150104179
    Abstract: An optical network unit (ONU) comprising a media access controller (MAC) configured to support biasing a laser transmitter to compensate for temperature related wavelength drift receiving a transmission timing instruction from an optical network control node, obtaining transmission power information for the laser transmitter, estimating a burst mode time period for the laser transmitter according to the transmission timing instruction, and calculating a laser phase fine tuning compensation value for the laser transmitter according to the burst mode time period and the transmission power information, and forwarding the laser phase fine tuning compensation value toward a bias controller to support biasing a phase of the laser transmitter.
    Type: Application
    Filed: October 14, 2014
    Publication date: April 16, 2015
    Inventors: Feng Wang, Xuejin Yan, Bo Gao, Frank Effenberger
  • Publication number: 20150104196
    Abstract: Exemplary embodiments of the present invention relate to electronic dispersion compensation (EDC). The interaction between the frequency chirp and the fiber dispersion is newly analyzed. The linear and nonlinear properties of the chirp-dispersion are separately analyzed. A pre-compensating transmitter may consist of a phase interpolator (PI), a 2 tap data generator, a pulse widening CLK generator, a rising pattern detector, 4:1 Mux and an output driver. A post-compensating receiver may consist of linear equalizer for the rabbit ear compensation, nonlinear equalizer for tilting compensation, typical high frequency boosting equalizer (EQ) and limiting amp (LA).
    Type: Application
    Filed: October 14, 2013
    Publication date: April 16, 2015
    Applicant: Korea Advanced Institute of Science and Technology
    Inventors: HyunMin BAE, KyeongHa KWON, JongHyeok YOON
  • Publication number: 20150086218
    Abstract: Methods and apparatus for managing the effects of dispersion in an optical transport system in which some of the system's nodes are connected to one another via inhomogeneous fiber-optic links. In one embodiment, an optical transmitter is configured to apply electronic and/or optical dispersion pre-compensation in the amount selected to cause the peak-to-average-power ratio of the optical signal in the lower-dispersion portion of the link to be relatively low (e.g., close to a minimum value). Advantageously, such dispersion pre-compensation tends to significantly reduce, e.g., in terms of the bit-error rate, the directional anisotropy exhibited by optical transmissions through the inhomogeneous fiber-optic links.
    Type: Application
    Filed: September 20, 2013
    Publication date: March 26, 2015
    Applicant: Alcatel-Lucent USA Inc.
    Inventors: Xiang Liu, Chandrasekhar Sethumadhavan, Peter J. Winzer
  • Patent number: 8989588
    Abstract: An optical transceiver includes an optical IC coupled to a processor IC. For transmit, the optical IC can be understood as a transmitter IC including a laser device or array. For receive, the optical IC can be understood as a receiver IC including a photodetector/photodiode device or array. For a transmitter IC, the processor IC includes a driver for a laser of the transmitter IC. The driver includes an equalizer that applies high frequency gain to a signal transmitted with the laser device. For a receiver IC, the processor IC includes a front end circuit to interface with a photodetector of the receiver IC. The front end circuit includes an equalizer that applies high frequency gain to a signal received by the receiver IC. The driver can be configurable to receive a laser having either orientation: ground termination or supply termination.
    Type: Grant
    Filed: January 22, 2013
    Date of Patent: March 24, 2015
    Assignee: Intel Corporation
    Inventors: Gil Afriat, Lior Horwitz, Dror Lazar, Assaf Issachar, Alexander Pogrebinsky, Adee O. Ran, Ehud Shoor, Roi Bar, Rushdy A. Saba
  • Publication number: 20150078762
    Abstract: To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus.
    Type: Application
    Filed: November 21, 2014
    Publication date: March 19, 2015
    Inventors: Koichi Ishihara, Takayuki Kobayashi, Riichi Kudo, Yasushi Takatori, Munehiro Matsui, Masato Mizoguchi, Akihide Sano, Shogo Yamanaka, Etsushi Yamazaki, Yutaka Miyamoto, Eiji Yoshida, Tadao Nakagawa
  • Publication number: 20150071641
    Abstract: An apparatus comprising a transmitter configured to generate an optical signal comprising a carrier modulated with at least two sidebands modulated with information, wherein the information introduces a separation gap in a frequency domain between the sidebands and the carrier, wherein one of the sidebands is an undesired sideband and another one of the sidebands is a desired sideband with a higher power intensity than the undesired sideband. A method comprising receiving an optical carrier from a light source and modulating the optical carrier with at least two sidebands modulated with information, wherein the information introduces a separation gap in a frequency domain between the sidebands and the optical carrier, wherein one of the sidebands is an undesired sideband and another one of the sidebands is a desired sideband having a higher power intensity than the undesired sideband.
    Type: Application
    Filed: September 12, 2013
    Publication date: March 12, 2015
    Applicant: Futurewei Technologies, Inc.
    Inventors: Yangjing Wen, Chunlei Liao, Xiao Shen, Yusheng Bai
  • Patent number: 8971719
    Abstract: An optical system may have an optical transmitter including a digital signal processor to receive a signal channel, add data corresponding to a pilot tone, generate a digital signal associated with the signal channel and including the pilot tone, and output the digital signal. The optical system may further have a digital-to-analog converter to convert the digital signal to an analog signal, a laser to provide an optical signal, and a modulator to receive the optical signal and the analog signal, and modulate the optical signal based on the analog signal to form a modulated optical signal. The modulated optical signal may include the pilot tone. The optical system may also have an optical receiver to receive the modulated optical signal, process the modulated optical signal to determine a phase associated with the pilot tone, and apply the phase to the modulated optical signal to recover the signal channel.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: March 3, 2015
    Assignee: Infinera Corporation
    Inventors: Pierre Herve Mertz, David J. Krause, Han Henry Sun
  • Patent number: 8964884
    Abstract: An apparatus configured to couple to a plurality of subscriber lines comprising a plurality of transmitters configured to couple to a plurality of physical channels and at least one virtual channel. The number of physical channels equals the number of subscriber lines. A processor is configured to compute a precoder matrix to minimize an error value. The error value accounts for an error on each channel subject to a constraint on power for each channel. A precoder is coupled to the processor and configured to use the precoder matrix to jointly process a plurality of data signals to generate a plurality transmit signals for the plurality of physical channels and the at least one virtual channel.
    Type: Grant
    Filed: December 31, 2012
    Date of Patent: February 24, 2015
    Assignee: Futurewei Technologies, Inc.
    Inventors: Xiao Liang, Chin Ngek Hung, Haixiang Liang
  • Patent number: 8948609
    Abstract: According to a first aspect, techniques are provided to optimize a Mach-Zehnder modulator drive waveform by distorting the outer modulation levels of the waveform, thereby equalizing eye openings of the received optical field, and in particular creating a wider and more defined central eye opening of the received optical field. According to a second aspect, techniques are provided to adjust in-phase (I) modulation levels based on the imperfect performance of a Mach-Zehnder modulator allocated to modulate quadrature-phase (Q) modulation levels, and conversely to adjust the Q modulation levels based on the imperfect performance of an MZ modulator allocated to modulate I modulation levels.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: February 3, 2015
    Assignee: Cisco Technology, Inc.
    Inventors: James Whiteaway, Thomas Duthel, Jonas Geyer
  • Patent number: 8948608
    Abstract: An optical modulator device directly-coupled to a driver circuit device. The optical modulator device can include a transmission line electrically coupled to an internal VDD, a first electrode electrically coupled to the transmission line, a second electrode electrically coupled to the first electrode and the transmission line. A wave guide can be operably coupled to the first and second electrodes, and a driver circuit device can be directly coupled to the transmission line and the first and second electrodes. This optical modulator and the driver circuit device can be configured without back termination.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: February 3, 2015
    Assignee: Inphi Corporation
    Inventor: Carl Pobanz
  • Patent number: 8934783
    Abstract: An Ethernet adapter system may include a transmitter to insert a payload type identifier sequence in a generic frame procedure header to indicate that a network is a converged enhanced Ethernet network. The transmitter may insert idle sequences in a stream of data frames transmitted along a link. The system may include a receiver to recognize a condition and to force a loss of synchronization condition on the link that will be converted by the receiver into a loss of light condition. The receiver may scan the transmitted stream of data frames for invalid data frames and introduce a code into the stream of data frames whenever an invalid data frame is detected.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: January 13, 2015
    Assignee: International Business Machines Corporation
    Inventors: Casimer M. DeCusatis, Thomas A. Gregg, Rajaram B. Krishnamurthy
  • Patent number: 8934786
    Abstract: An apparatus comprises an optical transmitter that comprises a processor and at least one optical modulator. The processor is configured to generate electronic representations of at least two pre-dispersion-compensated phase-conjugated optical variants carrying a same modulated payload data for transmission. The at least one optical modulator is configured to modulate the electronic representations, wherein an amount of dispersion induced on the pre-dispersion-compensated phase-conjugated optical variants depends on an accumulated dispersion (AD) of a transmission link through which the pre-dispersion-compensated phase-conjugated optical variants are to be transmitted. The amount of dispersion induced on the phase-conjugated optical variants may be approximately ?AD/2, where AD is the accumulated dispersion of the transmission link.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: January 13, 2015
    Assignee: Alcatel Lucent
    Inventors: Xiang Liu, Peter J. Winzer, Andrew Roman Chraplyvy, Robert William Tkach
  • Patent number: 8929747
    Abstract: A transmitter reduces or minimizes pulse narrowing. In one approach, an optical transmitter is designed to transmit data over an optical fiber at a specified data rate using on-off keying. The transmitter includes a pre-converter electrical channel and a limiting E/O converter. The pre-converter electrical channel produces a pre-converter signal that drives the limiting E/O converter. The pre-converter electrical channel is designed to reduce pulse narrowing in the pre-converter signal. In one implementation, the pre-converter electrical channel includes a pre-emphasis filter that is designed to minimize pulse width shrinkage.
    Type: Grant
    Filed: July 23, 2012
    Date of Patent: January 6, 2015
    Assignee: ClariPhy Communications, Inc.
    Inventor: Thomas A. Lindsay
  • Patent number: 8923696
    Abstract: Disclosed are an apparatus and method configured to process video data signals operating on a passive optical network (PON). One example method of operation may include receiving a data signal at an optical distribution network node (ODN) and identifying signal interference in the data signal. The method may also include modifying a shape of the data signal in the electrical domain and transmitting the modified data signal to at least one optical termination unit (ONT).
    Type: Grant
    Filed: June 20, 2012
    Date of Patent: December 30, 2014
    Assignee: Alcatel Lucent
    Inventors: James J. Stiscia, Joe L. Smith
  • Patent number: 8923706
    Abstract: An optical transmitter configured to perform digital signal equalization directed at mitigating the detrimental effects of a frequency roll-off in the transmitter's optical I-Q modulator. In various embodiments, a frequency-dependent spectral-correction function used for the digital signal equalization can be constructed to cause the spectrum of the modulated optical signal generated by the transmitter to have a desired degree of flatness in the vicinity of an optical carrier frequency and/or to at least partially mirror the frequency roll-off in the optical I-Q modulator.
    Type: Grant
    Filed: July 24, 2012
    Date of Patent: December 30, 2014
    Assignee: Alcatel Lucent
    Inventors: Chandrasekhar Sethumadhavan, Xiang Liu, Peter J. Winzer, Andrew Chraplyvy
  • Publication number: 20140376926
    Abstract: A photonic waveform generator and a method of generating an electrical waveform based on a photonic signal are disclosed. The generator includes an input port for receiving an optical signal, a pulse shaper coupled to the input port and configured to Fourier transform the optical signal and apply a pre-distort waveform onto optical spectrum of the optical signal, a dispersive pulse stretcher coupled to the pulse shaper, an optical-to-electrical converter coupled to the dispersive pulse stretcher, and an output port coupled to the optical-to-electrical converter, the pre-distortion removes distortion of the electrical signal that exists in the absence of the pre-distortion caused by violation of far field limitation between the optical signal and the electrical signal.
    Type: Application
    Filed: March 17, 2014
    Publication date: December 25, 2014
    Applicant: Purdue Research Foundation
    Inventors: Andrew Marc Weiner, Amir Dezfooliyan
  • Publication number: 20140376927
    Abstract: Linearized optical transmitter units are described for a hybrid optical fiber coaxial cable network. The linearized optical transmitter unit can comprise a directly-modulated or externally-modulated laser optically coupled to an optical conduit directed to an optical fiber communications link and electrically coupled to an electrical RF source line that provides an RF source to drive the laser or an external modulator for a light beam from the laser. A linearization information electrical component comprising memory and/or a processor, and a data output configured to transmit linearization enabling data for input into a direct digital synthesis engine that enables the direct digital synthesis engine to generate an RF signal wherein nonlinear responses of the transmitter and/or the optical fiber communications link are pre-compensated, in which the data is specific for the optical transmitter and/or the optical fiber communications link.
    Type: Application
    Filed: September 10, 2014
    Publication date: December 25, 2014
    Inventor: David Piehler
  • Publication number: 20140376925
    Abstract: A method modulates data for optical communication by first encoding the data using a forward error correction (FEC) encoder to produce encoded data, which are encoded using a block encoder to produce block encoded data such that Hamming distances between code words that represent the block encoded data are increased. The block encoded data are mapped to produce mapped data such that Euclidian distances between the constellation points are increased. Then, the mapped data are modulated in a transmitter to a modulated signal for an optical channel.
    Type: Application
    Filed: June 19, 2013
    Publication date: December 25, 2014
    Applicant: Mitsubishi Electric Research Laboratories, Inc.
    Inventors: Toshiaki Koike-Akino, Andrew Knyazev, David S Millar
  • Patent number: 8909064
    Abstract: Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator.
    Type: Grant
    Filed: April 11, 2014
    Date of Patent: December 9, 2014
    Assignee: Google Inc.
    Inventors: Bikash Koley, Vijayanand Vusirikala, Hong Liu
  • Patent number: 8909061
    Abstract: A method is provided for performing chromatic dispersion (CD) pre-compensation. The method generates an electronic signal at a transmitter, and uses a transmit CD compensation estimate to compute a CD pre-compensation filter. The transmit CD pre-compensation filter is used to process the electronic signal, generating a pre-compensated electronic signal. The pre-compensated electronic signal is converted into an optical signal and transmitted to an optical receiver via an optical channel. In one aspect, the transmitter generates a test electronic signal and the CD compensation estimate uses a first dispersion value to compute a first CD compensation filter. The transmitter accepts a residual dispersion estimate of the test optical signal from the first optical receiver CD compensation filter, generated from a (receiver-side) CD estimate, and then the transmit CD estimate can be modified in response to the combination of the first dispersion value and residual dispersion estimate.
    Type: Grant
    Filed: May 2, 2012
    Date of Patent: December 9, 2014
    Assignee: Applied Micro Circuits Corporation
    Inventor: Badri Varadarajan
  • Patent number: 8903238
    Abstract: A system, e.g. for optical communication, includes an I-Q modulator and a transmission signal processor. The I-Q modulator is configured to modulate a first light source in response to first I and Q modulation signals. The transmission signal processor is configured to receive a data stream including data corresponding to a first data subchannel. The processor maps the data subchannel to an optical transmission subchannel and outputs the first I and Q modulation signals. The I and Q modulation signals modulate the light source to produce an optical transmission signal that includes wavelength components corresponding to the optical transmission subchannel.
    Type: Grant
    Filed: September 10, 2012
    Date of Patent: December 2, 2014
    Assignee: Alcatel Lucent
    Inventors: Timo J. Pfau, Noriaki Kaneda, Young-Kai Chen
  • Patent number: 8897645
    Abstract: A system and method for improving receiver sensitivity of an DD-OFDM system without using frequency guard band. The method having: interleaving input data to the DD-OFDM system to generate interleaved data; encoding the input data with a first recursive systematic convolutional code to generate a first recursive systematic convolutional encoded data; encoding the interleaved data with a second recursive systematic convolutional code to generate a second recursive systematic convolutional encoded data; puncturing the first recursive systematic convolutional encoded data and the second recursive systematic convolutional encoded data to generate a parity sequence; and combining the input data with the parity sequence to generate coded DD-OFDM data; wherein the parity sequence is generated by using different puncturing rates for different OFDM subcarriers, so as to obtain higher spectral efficiency.
    Type: Grant
    Filed: December 1, 2010
    Date of Patent: November 25, 2014
    Assignee: ZTE (USA) Inc.
    Inventor: Jianjun Yu
  • Patent number: 8897654
    Abstract: A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.
    Type: Grant
    Filed: June 20, 2012
    Date of Patent: November 25, 2014
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Diego F. Pierrottet, Larry B. Petway, Farzin Amzajerdian, Bruce W. Barnes, George E. Lockard, Glenn D. Hines
  • Patent number: 8891974
    Abstract: A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and/or an optical fiber and may include a primary signal path for carrying an input signal and a secondary signal paths for generating distortion. The distortion compensation circuit may also include a controllable phase inverters and a tunable filter. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products and a tunable filter that adjusts the phase of the frequency dependent distortion. The phase inversion and tunable filter may be controlled in response to control signals generated based on one or more parameters such as, for example, laser power, input RF channel loading, temperature, and fiber length.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: November 18, 2014
    Assignee: Applied Optoelectronics, Inc.
    Inventor: Yi Wang
  • Patent number: 8886050
    Abstract: The present invention provides a wavelength division multiplexing system and a method and device for its residual dispersion compensation, wherein the device for residual dispersion compensation of wavelength division multiplexing system comprises: a performance parameter detecting device for receiving and detecting performance parameter of receiving terminal optical signal and sending detecting result of the performance parameter to a central control device; the central control device for deciding a dispersion regulating mode of a tunable dispersion compensator according to the detecting result of the performance parameter and sending the dispersion regulating mode to a tunable dispersion compensator control device through control signaling; and the tunable dispersion compensator control device for receiving the control signaling sent by the central control device and adjusting dispersion compensation amount of the tunable dispersion compensator according to the control signaling in order to make residual di
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: November 11, 2014
    Assignee: ZTE Corporation
    Inventors: Likun Zhang, Jiaying Wang
  • Publication number: 20140328584
    Abstract: An optical transmitter may include an optical source to provide a first optical signal having a varying frequency; an optical circuit to receive a portion of the first optical signal and provide a second optical signal corresponding to a change in frequency of the first optical signal; a photodetector to receive the first optical signal and provide an electrical signal that is indicative of the change in frequency of the first optical signal; an integrator to receive the electrical signal and provide an inverted electrical signal; and a controller to process the inverted electrical signal and provide a current, associated with the inverted electrical signal, to the optical source. The optical source may reduce the phase noise associated with the first optical signal based on the current.
    Type: Application
    Filed: March 27, 2013
    Publication date: November 6, 2014
    Applicant: Infinera Corporation
    Inventors: Han H. Sun, John D. McNicol, Kuang-Tsan Wu
  • Patent number: 8879904
    Abstract: An optical network and method of protection switching between first and second transceivers where dispersion compensation is effected electrically in the transmitters. The method includes detecting, at the second transceiver, a signal failure of a signal transmitted from the first transceiver and, upon detecting the signal failure, signaling the first transceiver to change its compensation function. The signaling can be done by encoding overhead bits in a signal transmitted from the second to the first transceiver. Another method of protection switching includes both transceivers toggling alternate reception paths upon detecting a signal failure and changing their dispersion compensation function to that of their respective alternate path.
    Type: Grant
    Filed: February 11, 2014
    Date of Patent: November 4, 2014
    Assignee: Rockstar Consortium US LP
    Inventors: James Harley, Gerard Swinkels, Michael Watford
  • Patent number: 8879925
    Abstract: An optical transmitter includes: a digital signal processor to generate a drive signal from input data; a controller to control an amplitude or power of the drive signal according to information relating to the digital signal processing of the digital signal processor; and an optical modulator to modulate input light with the drive signal controlled by the controller to generate an optical signal.
    Type: Grant
    Filed: December 8, 2011
    Date of Patent: November 4, 2014
    Assignee: Fujitsu Limited
    Inventors: Yuichi Akiyama, Takeshi Hoshida
  • Patent number: 8873970
    Abstract: A method for generating a 400 Gb/s single channel optical signal from multiple modulated subchannels includes carving respective modulated subchannels into return-to-zero RZ modulated subchannels having non-overlapping peaks with intensity modulators having a duty cycle less than 50%, and combining the subchannels into a single channel signal aggregating the bit rate of each of the subchannels. The subchannels are combined with a flat top optical component for increased subsequent receiver sensitivity.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Jianjun Yu, Dayou Qian, Philip Nan Ji, Ting Wang
  • Patent number: 8873972
    Abstract: An optical transmission apparatus includes an optical transmitter that outputs a signal light corresponding to a wavelength of a WDM light, a multiplexer that multiplexes lights input to the plurality of input ports, and that outputs a light generated through the multiplexing from the one or more output port, an optical amplifier that amplifies the light output from the multiplexer; and an amplified spontaneous emission (ASE) transmitter that inputs branching off part of the light output from the optical amplifier by a splitter and multiplexes, with the signal light, ASE in a wavelength band corresponding to an unused wavelength adjacent to the signal light included in the branched-off light.
    Type: Grant
    Filed: January 13, 2012
    Date of Patent: October 28, 2014
    Assignee: Fujitsu Limited
    Inventors: Takuya Miyashita, Takashi Toyomaki
  • Patent number: 8873971
    Abstract: Systems and methods are disclosed to perform nonlinear compensation (NLC) in an optical communication system by applying digital backpropagation (DBP) using a frequency-shaped split-step Fourier method (FS-SSFM), and processing a data block using an overlap-and-save method with a block size M and an overlap factor of N samples between adjacent blocks.
    Type: Grant
    Filed: October 10, 2011
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Ezra Ip, Neng Bai
  • Patent number: 8867928
    Abstract: Linearized optical transmitter units are described for a hybrid optical fiber coaxial cable network. The linearized optical transmitter unit can comprise a directly-modulated or externally-modulated laser optically coupled to an optical conduit directed to an optical fiber communications link and electrically coupled to an electrical RF source line that provides an RF source to drive the laser or an external modulator for a light beam from the laser. A linearization information electrical component comprising memory and/or a processor, and a data output configured to transmit linearization enabling data for input into a direct digital synthesis engine that enables the direct digital synthesis engine to generate an RF signal wherein nonlinear responses of the transmitter and/or the optical fiber communications link are pre-compensated, in which the data is specific for the optical transmitter and/or the optical fiber communications link.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: October 21, 2014
    Assignee: NeoPhotonics Corporation
    Inventor: David Piehler